[U-Boot] [PATCH v2 03/30] boot_fit: Create helper functions that can be used to select DTB out of FIT

[Franklin S Cooper Jr <fcooper@ti.com>]

Some platforms may append a FIT image to the U-boot image. This function
aids in parsing the FIT image and selecting the correct DTB at runtime.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
---
 common/Kconfig     |  8 ++++++++
 common/Makefile    |  1 +
 common/boot_fit.c  | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/boot_fit.h |  9 +++++++++
 include/image.h    |  8 ++++++++
 5 files changed, 84 insertions(+)
 create mode 100644 common/boot_fit.c
 create mode 100644 include/boot_fit.h

diff --git a/common/Kconfig b/common/Kconfig
index 1879aef..2429953 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -421,6 +421,14 @@ config SYS_STDIO_DEREGISTER
 
 endmenu
 
+config FIT_EMBED
+	bool "Support a FIT image embedded in the U-boot image"
+	default n
+	help
+	  This option provides hooks to allow U-boot to parse an
+	  appended FIT image and enable board specific code to then select
+	  the correct DTB to be used.
+
 config DEFAULT_FDT_FILE
 	string "Default fdt file"
 	help
diff --git a/common/Makefile b/common/Makefile
index ccd8bbc..0c6209b 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -151,6 +151,7 @@ obj-y += image.o
 obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o
 obj-$(CONFIG_$(SPL_)OF_LIBFDT) += image-fdt.o
 obj-$(CONFIG_$(SPL_)FIT) += image-fit.o
+obj-$(CONFIG_FIT_EMBED) += boot_fit.o common_fit.o
 obj-$(CONFIG_$(SPL_)FIT_SIGNATURE) += image-sig.o
 obj-$(CONFIG_IO_TRACE) += iotrace.o
 obj-y += memsize.o
diff --git a/common/boot_fit.c b/common/boot_fit.c
new file mode 100644
index 0000000..ff26cf7
--- /dev/null
+++ b/common/boot_fit.c
@@ -0,0 +1,58 @@
+/*
+ * (C) Copyright 2017
+ * Texas Instruments, <www.ti.com>
+ *
+ * Franklin S Cooper Jr. <fcooper@ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <boot_fit.h>
+#include <common.h>
+#include <errno.h>
+#include <image.h>
+#include <libfdt.h>
+
+int fdt_offset(void *fit)
+{
+	int fdt_offset, fdt_len;
+	int images;
+
+	images = fdt_path_offset(fit, FIT_IMAGES_PATH);
+	if (images < 0) {
+		debug("%s: Cannot find /images node: %d\n", __func__, images);
+		return -1;
+	}
+
+	/* Figure out which device tree the board wants to use */
+	fdt_len = fit_select_fdt(fit, images, &fdt_offset);
+
+	if (fdt_len < 0)
+		return fdt_len;
+
+	return fdt_offset;
+}
+
+void *locate_dtb_in_fit(void *fit)
+{
+	struct image_header *header;
+	int size;
+	int ret;
+
+	size = fdt_totalsize(fit);
+	size = (size + 3) & ~3;
+
+	header = (struct image_header *)fit;
+
+	if (image_get_magic(header) != FDT_MAGIC) {
+		debug("No FIT image appended to U-boot\n");
+		return NULL;
+	}
+
+	ret = fdt_offset(fit);
+
+	if (ret <= 0)
+		return NULL;
+	else
+		return (void *)fit+size+ret;
+}
diff --git a/include/boot_fit.h b/include/boot_fit.h
new file mode 100644
index 0000000..b7d2462
--- /dev/null
+++ b/include/boot_fit.h
@@ -0,0 +1,9 @@
+/*
+ * Copyright (C) 2017 Texas Instruments
+ * Written by Franklin Cooper Jr. <fcooper@ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+int fdt_offset(void *fit);
+void *locate_dtb_in_fit(void *fit);
diff --git a/include/image.h b/include/image.h
index 3f26f9b..1083578 100644
--- a/include/image.h
+++ b/include/image.h
@@ -18,6 +18,7 @@
 
 #include "compiler.h"
 #include <asm/byteorder.h>
+#include <linux/kconfig.h>
 
 /* Define this to avoid #ifdefs later on */
 struct lmb;
@@ -1274,6 +1275,13 @@ int board_fit_config_name_match(const char *name);
 void board_fit_image_post_process(void **p_image, size_t *p_size);
 #endif /* CONFIG_SPL_FIT_IMAGE_POST_PROCESS */
 
+#if IS_ENABLED(CONFIG_SPL_LOAD_FIT) || IS_ENABLED(CONFIG_FIT_EMBED)
+
+ulong fdt_getprop_u32(const void *fdt, int node, const char *prop);
+int fit_select_fdt(const void *fdt, int images, int *fdt_offsetp);
+
+#endif
+
 /**
  * Mapping of image types to function handlers to be invoked on the associated
  * loaded images
-- 
2.10.0